1981 Volume 67 Issue 14 Pages 2131-2137
The equilibrium concentrations of Ti3+ and Ti4+ in the molten CaO-SiO2-Al2O3-MgO system with TiC, C and atmospheric CO were determined in the temperature ranging from 1 400° to 1 550°C in order to clarify the mechanism of the formation of titanium carbonitride at the hearth of a blast furnace. The γTio1·5 and γTio2 values were calculatcd from the determined concentrations as well.
The Ti4+ ion in slags is found to behave amphoterically with the critical CaO/SiO2 equal to unity. The Ti3+ ion behaves basic except in highly basic slags such as in the CaO-Al2O3 system, where it turns out to behave acidic.
It is indicated by the thermodynamic calculation including the data of the present work that the actual blast furnace slag contains titanium abundantly enough to form Ti(CN). In view of the sluggish formation of TiC from slags and graphite, the protective titanium bear on the hearth is likely to form on the reaction in which hot metals take nart.